Isthmic spondylolisthesis in symptomatic and asymptomatic subjects, epidemiology, and natural history with special reference to disk abnormality and mode of treatment

Observations during the past 35 years on operative and conservative treatment of adult and young patients with isthmic spondylolisthesis, demonstrate the main indications of fusion are pain and risk of further progression of the slip. At one time, posterior fusion was recommended. Posterolateral fusion in situ was adopted in 1975, and during the past ten years anterior fusion combined with reduction and transpedicular fixation has been performed in severe slips. Surgery was mainly indicated to alleviate pain or to prevent further progression of the slip. It seems possible to alter the natural course of the disease by operation, but it is difficult to prove the connection between the radiographic findings and the pain. The epidemiologic study shows that the prevalence of spondylolisthesis in Finland is 6%, but there are no significant differences between these subjects and controls without spondylolisthesis. Symptomatic patients may have pain, however, even after a long observation time. Prevention of the slip is difficult because, statistically, 90% of the slip has already occurred when the patient is first seen. Posterolateral fusion in situ is the method of choice, especially for most young patients. Anterior fusion is indicated if the slip is greater than 40%-50%. Reduction of the slip is indicated in exceptional cases only.     

Severe primary HIV-1 infection among black persons in Barbados

The purpose of this long-term follow-up was (1) to investigate disc changes in the olisthetic segment in patients treated conservatively, (2) to compare disc changes above the slipped vertebra in conservatively treated patients with those in operatively treated patients, and (3) to establish possible relations of disc changes to the degree of the slip and to subjective back pain symptoms of the patients. The subjects were 227 patients with isthmic L5 olisthesis diagnosed under 20 years of age (mean 13.8 years) with a mean follow-up of 15.4 (range 5-30) years. Of these, 145 patients had been treated with segmental fusion and 82 had been treated conservatively. At follow-up, standing anteroposterior and lateral radiographs as well as flexion/extension views of the lumbar spine were taken. Disc degeneration was graded semiquantitatively: 0 = normal disc height, 1 = decrease of disc height < 50%, 2 = decrease > or = 50%, and 3 = obliteration of the disc. In the conservatively treated patients degeneration of the olisthetic disc was distributed by grade as follows: O: n = 38, 1: n = 24, 2: n = 14, 3: n = 6. No motion at all was observed in the olisthetic segment in 40 patients (48%) with a mean slip of 30%, segmental motion of 4 degrees-18 degrees was found in 42 patients with a mean slip of 14%. There was a statistically significant association of the degree of slip to the severity of disc degeneration and non-mobility of the segment. Grade 1 degeneration of the L4/5 disc occurred in 25.6% of the conservatively treated patients and in 32% of 48 patients treated with L5-S1 fusion. This correlated with the severity of the slip, but not with pain symptoms or pathologic segmental mobility at the time of follow-up. Out of 84 patients with L4-S1 fusion, in 17% grade 1 degeneration of the L3/4 disc was observed, and 3 out of 13 patients (23%) with L3-S1 fusion had grade 1 degeneration of the disc above the fusion. The disc changes had no correlation with subjective pain symptoms. It is concluded that the natural course of isthmic spondylolisthesis is associated with disc degeneration and spontaneous stabilization of the olisthetic segment. Fusion operations do not significantly increase the rate of disc degeneration in the adjacent disc above the fusion after a mean postoperative follow-up of 13.8 years. No correlation between the number of degenerated discs or the degree of degeneration and subjective low back pain symptoms was found.     

Analysis and treatment of poor outcomes following in situ arthrodesis in adolescent spondylolisthesis

In situ lumbosacral arthrodesis in the treatment of adolescent spondylolisthesis was evaluated in 39 patients. The clinical outcome an average of 4.7 years later was considered excellent or good in 82% of the cases based on their pain and gait. The quality of the fusion mass correlated with outcome. Those patients with the most severe kyphosis (slip angle) had the greatest chance of a poor result. Four patients required reoperation for pseudarthrosis or symptomatic compression of the cauda equina. Three of these were successfully treated with repeat arthrodesis or decompression with sacroplasty or both.     

A patient with aortic dissection and abdominal aortic aneurysm with fistula

Aneurysm of the abdominal aorta is not uncommon in later life. The frequency of aneurysm rupture varies with aneurysm diameter. In rare cases, the aneurysm may rupture intra-abdominally into surrounding structures and give rise to a fistula. When blood vessels are involved, the commonest form is aortocaval fistula, the presenting symptoms being those of severe right-ventricular heart failure. Although thoracic aorta dissection may be made manifest in acute intense chest pain, it is asymptomatic in up to 50 per cent of cases. The article consists in a case report of asymptomatic thoracic aorta dissection occurring concomitantly with a ruptured abdominal aneurysm the symptoms of which were severe right ventricular heart failure due to an aortocaval fistula causing increased pressure, and severe bilateral oedema of the legs. If the rare complication of an aortocaval fistula could be detected earlier, it might be possible to prevent progression to refractory cardiac failure. The possibility of a fistula should be borne in mind if haematuria is present in a case of abdominal aneurysm or a pulsatile abdominal mass is present in conjunction with a murmur.     

Regression of severe atherosclerotic plaque in patients with mild elevation of LDL cholesterol

BACKGROUND: Intensive risk factor reduction in patients with dyslipidemias and coronary atherosclerosis has been shown to result in alterations in coronary artery morphology and reduced clinical events. However, the impact of such interventions in populations with relatively normal levels of low-density lipoproteins (LDL) is unclear. METHODS: To test the hypothesis that intensive risk factor reduction results in angiographic regression in patients with only mildly elevated levels of LDL, 14 patients with angiographically proven coronary atherosclerosis were entered into the University of California Davis Coronary Artery Disease Regression Program and intensively treated with pharmacologic and nonpharmacologic interventions for 2 years. Quantitative angiography was performed prior to and after 2 years of therapy to determine changes in coronary artery diameter. RESULTS: As a result of this program, dietary fat intake was reduced by 58% and LDL fell from 120 +/- 7 mg/dL to 104 +/- 6 mg/dL (p = 0.05). The average diameter of the measured arterial locations (including all 53 stenoses and 292 nondiscrete regions) on study entry was 2.74 +/- 0.05 mm. After 24 months, there was a net increase in arterial diameter (regression) of +0.05 +/- 0.04 mm to 2.81 +/- 0.05 mm (p = 0.01). While there was no significant change in the average diameter of discrete stenoses, all 8 lesions > or = 50% initial diameter narrowing regressed, with a mean diameter change of + 0.2 mm. Conversely, only 1 of 8 mild lesions < or = 20% regressed, while 4 progressed. Intermediate lesions (20% to 50%, n = 37) had balanced progression and regression. CONCLUSIONS: When examined as a continuous variable, there was a significant linear correlation between initial lesion severity (% stenosis) and the extent of regression (mm). Therefore, risk factor reduction (dietary therapy, exercise, psycho-social counseling, and lipid lowering therapy) in patients with only mild dyslipidemia results in angiographic regression of more severe lesions (> 50% initial stenosis), but does not prevent progression of mild lesions (< 20%). These findings demonstrate that intensive risk factor reduction in patients with only mild elevation of lipids beneficially influences the morphology of the most severe lesions.     

Surgical treatments for orthopaedic complications in long-term haemodialysis patients--a review of 546 cases over the last 8 years

We reviewed 546 operative cases in haemodialysis patients during the past 8 years between June 1990 and May 1998. The average age of the 257 male and the 289 female patients was 57.1 years. The average period of haemodialysis was 14 years and 4 months. We discussed the etiology, pathological focus, frequency, symptoms, problems and operative indications. Carpal tunnel syndrome occurred most frequently, occupying 289 cases. Short-term postoperative results were positive in the initial case within 6 months after the occurrence of the first symptoms. Because no effective method preventing recurrence existed, synovectomy was used as much as possible in the initial operation. Surgical treatment was used for amyloid arthropathy in 15 shoulders. It was effective in cases resistant to any conservative treatment. For the knee joint, the arthroscopic synovectomy was performed in 8 cases, and total knee replacement in 6 cases. The results of the total knee replacement cases were good. However, recurrences were observed in 40% of the synovectomy cases. In the hip joint, the curettage and bone grafting were performed in 7 hips of 6 patients. All bone grafts were consolidated and there was no case of postoperative pathological fracture. In some cases with destructive spondyloarthropathy, the vertebrae involved spontaneously fused without severe kyphotic deformity. A case with mild pain and without neurological deficit can be treated conservatively. A case with severe pain, instability, and myelopathy indicates operative measures must be taken. Attention must be paid for a possible collapse of the grafted bone after the cervical level two anterior fusion. Haemodialysis patients are vulnerable to infection. This diagnosis is difficult to distinguish due to the weakened state of the immune system. Rigorous attention is required to prevent and detect infection in cases using artificial joints or instrumentation. The treatment of bone and joint disturbances from dialysis-related amyloidosis has become surgical due to the advancement of dialysis control. However, it remains one of the more conservative treatments. Determining the cause and establishing a method of treatment are desired as early as possible.     

Spondylolisthesis in children and adolescents

A study of spondylolysis and spondylolisthesis in 142 children and adolescents is reported. In twelve of the seventy-nine patients followed for over a year the affected vertebra slipped further by 10 per cent or more. Increasing slip occurred mainly during the adolescent growth spurt, and was greater when spinal bifida or other vertebral anomalies were present. If at presentation the slip is less than 30 per cent then further slip beyond 30 per cent is unlikely. Decompression posteriorly is advised when signs of nerve pressure are present. Indications for spinal fusion are suggested; the intertransverse method of fusion was used in sixty-nine patients.     

Evaluation of patients with bladder outlet obstruction and mild international prostate symptom score followed up by watchful waiting

OBJECTIVES: To examine the variability of bladder outlet obstruction and mild lower urinary tract symptoms in patients with benign prostatic hyperplasia (BPH) followed up by watchful waiting. METHODS: The International Prostate Symptom Score (IPSS) has four questions related to voiding symptoms and three related to filling symptoms. Scores of 0 to 7, 8 to 19, and 20 to 35 represent mild, moderate, and severe symptoms, respectively. Over a period of 36 months the IPSS questionnaire was administered to 479 patients 50 to 81 years old (mean age 63) with BPH. A pressure-flow study was used to determine the presence of bladder outlet obstruction. On the basis of their scores, the patients were classified into 50 with mild, 227 with moderate, and 202 with severe symptoms. In the present study only patients with a mild score were analyzed. RESULTS: Of 50 patients with mild symptoms, 16 (32%) had bladder outlet obstruction. After a period of 9 to 22 months (mean 17) of watchful waiting, these 16 patients were reviewed. Twelve (75%) of the 16 had bladder outlet obstruction reconfirmed by pressure-flow studies, and 3 (18.8%) of 16 had increased symptoms (moderate symptomatic) and underwent treatment (1 began pharmacologic treatment, and 2 chose transurethral resection). A total of 4 (25%) of 16 patients still had mild voiding disturbances and refused the second urodynamic evaluation. The remaining 34 patients with no obstruction had annual routine follow-up and had persistent mild symptom scores and normal uroflowmetric results. These patients did not undergo another pressure-flow evaluation. CONCLUSIONS: A pressure-flow study is routinely avoided in patients with a mild IPSS. From symptoms alone it was not possible to diagnose bladder outlet obstruction in these patients. Pressure-flow studies and symptom profiles measure different aspects of the clinical condition. After a mean follow-up of 17 months of watchful waiting, 13 (81.2%) of 1 6 patients were clinically stable. Because the need for therapy is dictated by quality of life, it is difficult to propose treatment for patients with minimal symptoms, even in the presence of bladder outlet obstruction.     

Regression of hepatic fibrosis in hepatitis C with long-term interferon treatment

We report the case of a 53-yr-old woman who developed an ulcer of the distal rectum with mild stenosis after prolonged use of suppositories containing paracetamol, caffeine, and codeine. After undergoing extensive diagnostic tests with exclusion of other possible causes, she admitted to the abuse of the suppositories. She was treated with frequent endoscopic balloon dilations to prevent progression of the rectal stenosis. Because of severe pain on defecation, she needed a protective colostomy which could be closed after the healing of the ulcer 7 months later. There was no significant residual stenosis. This case is compared to cases described in the past 30 years.     

The possibility of resuscitating livers after warm ischemic injury

The onset and course of ulcerative colitis diagnosed in 38 children at or before 10 years of age were reviewed. The mean age at onset was 5.9 years. A family history of inflammatory bowel disease was present in 24% of patients, and 13% had a history of cow milk allergy in infancy. Initially, by radiologic or colonoscopic studies, 71% had total colonic disease, 13% had left-sided colitis, and 6% had proctitis; extensive examination was not performed in 4 patients. Four patients (11%) presented with severe colitis, 14 (37%) with moderate colitis, and 20 (53%) with mild colitis. The most frequent symptoms were abdominal pain (94%), diarrhea (84%), and rectal bleeding (84%). Between 2 and 10 years after diagnosis, 89% of children had total colonic disease and 11% had left-sided disease. All four patients with severe disease at onset responded to medical therapy with one having a colectomy 15 years later with pathology consistent with Crohn's disease. Of those with moderate disease, half had infrequent moderate recurrences and half had intermittent mild disease. One patient had colectomy at 21 years for intractable disease. Of the 20 with mild disease, 16 continued to have intermittent mild recurrences, 1 had chronic mild disease, 2 had moderate recurrent disease, and 1 has remained asymptomatic for 5 years. Psychiatric disturbances requiring therapy were identified in 5 (13%) children. Results are encouraging: after the first 2 years of illness, two thirds of the children have had subsequent mild colitis with infrequent relapses and three quarters consider their life to be of good quality.     

Posterolateral fusion for radicular pain in isthmic spondylolisthesis

Reported is the outcome for 25 patients in whom spondylolisthesis with radicular pain was treated by posterolateral fusion alone (Group A). These outcomes are compared with those obtained in 23 other patients with the same symptomatology and spondylolisthesis treated by root release and posterolateral fusion (Group B). Most patients had Grade I or II isthmic spondylolisthesis. Results were assessed functionally and radiographically with an average followup of 32 months. Posterolateral fusion in situ provided excellent or good results in 88% of patients according to the modified classification of Stauffer and Coventry. In Group A, radicular pain at exertion disappeared in 92% of patients, and radicular pain at rest disappeared in 88%. In Group B, radicular pain at exertion disappeared in 65% of patients, and radicular pain at rest disappeared in 70%. There was no significant statistical difference between the 2 groups. Resection of the loose lamina and root decompression do not seem to be mandatory. The overall fusion rate was 81%. Instrumentation in case of instability and the use of allografts are advised.     

Surgical treatment of herniation of a lumbar intervertebral disk in young people (author's transl)

Among 2755 patients operated on for nerve-root compression there were 38 children and juveniles (aged 11-22 years). Average interval between onset of symptoms and operation was 14 1/2 months and often involved considerable diagnostic effort. 36 of the 38 patients were re-examined an average of 11 years after operation: 15 were free of symptoms, 18 had occasional mild symptoms, two had continuous mild pain and one had occasional severe pain. Re-operation was necessary in six. All patients are able to work. A connection between an accident and the herniation was demonstrated in only two instances.     

High resting energy expenditure in normal-weight bulimics and its normalization with control of eating behaviour

Combined anterior and posterior fusion with posterior instrumentation may be indicated in the treatment of select cases of L5-S1 spondylolisthesis. The instrumentation, however, is expensive and usually bulky, occasionally requiring removal. In an effort to avoid these problems, an L5-S1 paralaminar screw technique was developed for posterior stabilization after an L5-S1 anterior interbody fusion. The technique involves the placement of cortical screws from the base of the articular process of S1 to the pedicle of L5. This study evaluates the anatomic applications and clinical results of this technique. The relationship between the screw and L5 nerve root was examined using five cadaveric specimens with olisthesis of 0, 25, 50, and 75%. This work demonstrates that the screws can only be inserted safely if an L5-S1 olisthesis of at least 25% is present. If < 25%, the screws will either impinge on or directly injure the L5 nerve root. In the clinical study, the outcomes of 20 patients who had an isthmic spondylolisthesis of 25-81% and were treated with partial reduction, L5-S1 anterior interbody fusion, and L5-S1 posterior paralaminar screw fixation were reviewed. Nineteen patients had adequate posterior stabilization to completely heal an L5-S1 anterior interbody fusion without loss of the correction. In one patient, a pseudarthrosis occurred secondary to poor surgical technique of both anterior and posterior fusions. This patient required an additional L4-S1 posterior fusion 9 months later and had a good clinical outcome. No other complications due to screw placement occurred. We conclude that this procedure can be used safely and reliably for the posterior stabilization of L5-S1 after stable anterior L5-S1 interbody fusion in residual slips of at least 25%. Prerequisites are proper patient compliance and low weight. Compared with other posterior instrumentation systems, this screw fixation is inexpensive and does not require implant removal. The disadvantages of the method are the degree of difficulty of the procedure and the limited clinical application to cases of L5-S1 spondylolisthesis with corrected residual slips of 25 to 50-60%. The procedure is technically demanding and should be limited to those surgeons who are comfortable with the method.     

Ketorolac. A reappraisal of its pharmacodynamic and pharmacokinetic properties and therapeutic use in pain management

Ketorolac is a nonsteroidal anti-inflammatory drug (NSAID) with strong analgesic activity. The analgesic efficacy of ketorolac has been extensively evaluated in the postoperative setting, in both hospital inpatients and outpatients, and in patients with various other acute pain states. After major abdominal, orthopaedic or gynaecological surgery or ambulatory laparoscopic or gynaecological procedures, ketorolac provides relief from mild to severe pain in the majority of patients and has similar analgesic efficacy to that of standard dosages of morphine and pethidine (meperidine) as well as less frequently used opioids and other NSAIDs. The analgesic effect of ketorolac may be slightly delayed but often persists for longer than that of opioids. Combined therapy with ketorolac and an opioid results in a 25 to 50% reduction in opioid requirements, and in some patients this is accompanied by a concomitant decrease in opioid-induced adverse events, more rapid return to normal gastrointestinal function and shorter stay in hospital. In children undergoing myringotomy, hernia repair, tonsillectomy, or other surgery associated with mild to moderate pain, ketorolac provides comparable analgesia to morphine, pethidine or paracetamol (acetaminophen). In the emergency department, ketorolac attenuates moderate to severe pain in patients with renal colic, migraine headache, musculoskeletal pain or sickle cell crisis and is usually as effective as frequently used opioids, such as morphine and pethidine, and other NSAIDs and analgesics. Subcutaneous administration of ketorolac reduces pain in patients with cancer and seems particularly beneficial in pain resulting from bone metastases. The acquisition cost of ketorolac is greater than that of morphine or pethidine; however, in a small number of studies, the higher cost of ketorolac was offset when treatment with ketorolac resulted in a reduced hospital stay compared with alternative opioid therapy. The tolerability profile of ketorolac parallels that of other NSAIDs; most clinically important adverse events affect the gastrointestinal tract and/or renal or haematological function. The incidence of serious or fatal adverse events reported with ketorolac has decreased since revision of dosage guidelines. Results from a large retrospective postmarketing surveillance study in more than 20,000 patients demonstrated that the overall risk of gastrointestinal or operative site bleeding related to parenteral ketorolac therapy was only slightly higher than with opioids. However, the risk increased markedly when high dosages were used for more than 5 days, especially in the elderly. Acute renal failure may occur after treatment with ketorolac but is usually reversible on drug discontinuation. In common with other NSAIDs, ketorolac has also been implicated in allergic or hypersensitivity reactions. In summary, ketorolac is a strong analgesic with a tolerability profile which resembles that of other NSAIDs. When used in accordance with current dosage guidelines, this drug provides a useful alternative, or adjuvant, to opioids in patients with moderate to severe pain.     

Anterior discectomy and fusion for painful cervical disc disease. A report of 50 patients with an average follow-up of 21 years

STUDY DESIGN: This is a retrospective long-term clinical and roentgenographic review of 50 patients who underwent anterior discectomy and fusion for painful cervical disc disease. The patients were reviewed by the senior author. OBJECTIVE: To evaluate the long-term effectiveness of anterior cervical discectomy and fusion and identify clinical and roentgenographic factors that may increase the chances of recurrent problems. SUMMARY OF BACKGROUND DATA: Many studies have demonstrated the initial effectiveness of this procedure; however, there are no previously published reports that include the results of a 21-year follow-up period. METHODS: Office charts and hospital records were used to obtain information about diagnosis, surgery, and complications. On follow-up examination, all patients were interviewed and examined, and roentgenograms were obtained. RESULTS: Forty-eight patients had initial pain relief, and of these, 32 remained pain-free an average of 21 years after surgery. Sixteen had recurrent pain an average of 7.2 years after surgery. Eight of these required surgery for disc disease at an adjacent level. The abrupt onset of pain was the only clinical or roentgenographic factor that correlated with recurrent pain. CONCLUSION: Anterior cervical discectomy and fusion yield excellent initial results. However, patients must be cautioned that recurrent symptoms can occur, and, in a small percentage of patients, the symptoms may be severe enough to require additional surgery.     

Dermatological indicators of coronary risk: a case-control study

Varicella pneumonia is the most common complication of adult varicella. Symptoms may be severe and the mortality rate high in patients who are immunodeficient or pregnant. Symptoms may be mild and progression more favorable in adults previously in good health. We report two cases of varicella infection complicated by severe pulmonary involvement in adult patients who were previously healthy. Case 1 was a 36-year-old male who 6 days after developing varicella was clinically observed to have dyspnea and hemopytsis. He died of acute respiratory failure on the following day. Case 2 was a 28-year-old male whose respiratory symptoms started the third day after developing varicella. These symptoms were relieved by treatment with acyclovir and gammaglobulin. Careful observation is and an early treatment of varicella should be undertaken not only for patients with suppressed cellular immunity, but also for healthy adults, to prevent severe complications.     

Surgical treatment of Crohn disease in children and adolescents; how conservative can the paediatrician be?

Thirty-eight children (21 male, 17 female, age 3-18 years), treated for Crohn disease in two Dutch university centres, were retrospectively studied in order to evaluate the results of conservative treatment and to find out in what way surgical treatment in this age group may have differed from treating adults with this disease. Both groups had an equal distribution of age and sex. Diarrhoea with discharge of blood and mucus, abdominal pain, nausea/vomiting, weight loss, fever and general discomfort were the most frequent presenting symptoms. Twenty-three children (60%) showed signs of malabsorption; 4 children (10%) had growth retardation. In 27 children (70%), 63 surgical procedures were performed (2.4 operations per child). There was no surgical mortality. Most operations were performed for ileocolitis and colon-only localizations needed most re-operations. Of the surgical procedures performed, 55% were excisional procedures. Already 3 years after the onset of symptoms, 50% of all children had had their first resection, whereas in adults, 50% of the patients undergo surgery 8 years after disease onset. Eight children were treated with split ileostomy. In only one of these children, operated for non-toxic colitis and severe steroid-dependent growth retardation, could the colon eventually be saved. The time between the onset of symptoms and the first operation seems to be shorter in children compared to adults. Severe malabsorption and growth retardation are additional specific indications for surgery for Crohn disease in childhood. The latter combined with non-toxic colitis, may perhaps be the only indication left for performing split ileostomy in Crohn disease.     

Lumbar intervertebral disc herniation in children less than 16 years of age. Long-term follow-up study of surgically managed cases

STUDY DESIGN: In this retrospective study, the long-term clinical results of lumbar intervertebral disc herniation in children less than 16 years of age were reviewed. OBJECTIVES: To evaluate the effectiveness of surgical treatment including posterior discectomy, extraperitoneal anterolateral discectomy, and anterior interbody fusion for lumbar intervertebral disc herniation in children less than 16 years of age. SUMMARY OF BACKGROUND DATA: Although previous follow-up studies on surgically managed lumbar intervertebral disc herniation in children and adolescents generally reveal good outcomes, few reports have focused on the time course of clinical findings and the long-term results. METHODS: The outcome of subjective symptoms, clinical signs, and time-related change of the intervertebral disc space in 11 patients were evaluated with an average follow-up period of 9 years (range, 5-12 years). RESULTS: The posterior discectomy procedure relieved clinical symptoms quickly. In the case of central herniation with or without intervertebral instability, extraperitoneal anterolateral discectomy or anterior interbody fusion led to favorable long-term results. Clinical symptoms (lower back pain, leg pain) and neurologic disturbance disappeared within 3 months after surgery. Recovery of normal straight leg raising test results (tight hamstrings), however, required much more time than recovery of other symptoms. Narrowing of the intervertebral disc space progressed up to 3-6 months after discectomy, but then disc space widening occurred. CONCLUSIONS: Satisfactory long-term clinical results and early return to school life were obtained with each surgical procedure. It is important to aim toward an early return to school via surgical treatment.     

Estimating energy intake of urban women in Colombia: comparison of diet records and recalls

A total of 611 Schistosoma mansoni infected primary school children from three schools in north-east Ethiopia were treated with praziquantel at 40 mg/kg body weight in a single dose. Pre-treatment, 40.4% had no presenting symptoms and 30-40% had nausea, abdominal cramps and/or bloody-mucoid diarrhoea. None of the pre-treatment symptoms was related to nutritional status, intensity of S. mansoni egg excretion, or to the presence of other concomitant intestinal parasitic infections. During the first 4-6 h post-treatment observation period, 90 (14.7%) children self-presented with severe gastro-intestinal symptoms. Children who self-presented with severe symptoms had a higher mean age and mean S. mansoni egg excretion compared with children who did not self-present. The following day a total of 529 (86.6%) children, including all who self-presented during the first 4-6 h post-treatment, reported for clinical check-up and were subjected to a structured questionnaire interview on symptoms they had experienced over the time lapse following treatment. Among these, 91.5% reported one or more treatment related symptoms which were at times severe. Abdominal cramps (86.9%), diarrhoea with blood and/or mucus (49.5%), dizziness (31.2%) and vomiting (24.9%) were the most common treatment related symptoms. Skin rash with oedema were observed in four cases. Among treatment related symptoms, the combination of abdominal cramps with vomiting, bloody diarrhoea, vomiting alone and general weakness were significantly higher among the malnourished. A proportion of these symptoms increased with increasing categories of S. mansoni egg excretion before and after adjusting for nutritional status and concurrent intestinal parasitic infections. Overall, the cure rate of praziquantel, among 541 children who had stool examination 5 weeks after treatment was 83.2% and this rate decreased with increasing pre-treatment egg counts. In conclusion, most of the treatment related symptoms were mild. However, some of the objective symptoms were at times severe and may reduce drug compliance in primary health care based population chemotherapy.